1. Field of the Invention
This invention generally relates to a wave-propelled marine vessel and, more particularly, to a vessel which is advanced along an intended forward direction by the direct conversion of rising and falling water currents of a wave.
2. Description of Related Art
It has previously been proposed to utilize kinetic energy contained in sea waves to propel a ship. Generally speaking, the up-and-down motion of wave currents near the water-air interface is harnessed to generate a forward thrust having a horizontal component in order to forwardly propel the ship.
In some cases, this conversion of the wave kinetic energy is indirect. More specifically, the up-and-down motion of the water currents moves a floating body up and down, and this movement of the floating body is employed, for example, to rotate a propeller shaft to drive a turbine or an air compressor. These indirect conversion arrangements call for complex and elaborate machinery and, in any event, do not efficiently harness the kinetic energy contained in the waves.
Of greater promise, because of their greater efficiency, are arrangements which seek to convert the kinetic energy contained in the waves directly to a forward thrust having a horizontal component. These direct conversion arrangements utilize fins pivotable about respective axes situated forwardly of the center of hydrodynamic resistance of the vessel. The rising and falling water currents act on the pivotable fins to orient them in such a way that these currents are deflected generally rearwardly of the fins, thereby forwardly propelling the vessel.
Although generally satisfactory for their intended purpose, the known direct conversion arrangements have not proven to be altogether efficient in forwardly propelling a vessel. The horizontally-directed forward propulsion force that could have been efficiently harnessed from the water currents was limited by the mass, weight, buoyancy and inertia of the vessel itself. If the ratio of the driving force of the wave to the resisting force, e.g. mass, of the vessel became too large, then the vessel would move together with the driving force. This tended to decrease the velocity of the water currents deflected rearwardly of the vessel and, in turn, also decreased the speed of the vessel.
Exemplificative of prior art wave-propelled vessels are the following patents:
U.S. 1,448,029 PA0 U.S. 1,532,459 PA0 U.S. 1,705,430 PA0 U.S. 3,872,819 PA0 U.K. 190,867 PA0 U.K. 377,851 PA0 U.K. 914,997 PA0 U.K. 2,045,708 PA0 France 393,899 PA0 France 627,201 PA0 France 657,539 PA0 France 810,834 PA0 France 2,408,517 PA0 France 2,553,373 PA0 Belgium 570,555 PA0 Belgium 745,202 PA0 Japan 58-30893 PA0 Germany 189,767 PA0 Germany 189,768 PA0 Germany 27 40 939 PA0 Germany DE 3129819 PA0 Germany DE 3303535 PA0 PCT Internat'l WO 80/01674